Track assembly for irrigation systems

ABSTRACT

A track assembly for a mobile tower of an irrigation system includes: a mounting bracket configured to be attached to the mobile tower; a gearbox assembly and rotatable drive wheel hub attached to the mounting bracket; a drive wheel attached to the drive hub; rotatable tension wheel hub attached to the mounting bracket and spaced from the drive hub; a tension wheel attached to the tension wheel hub; and a track trained over the drive wheel and the tension wheel and driven by the drive wheel to propel the mobile tower.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to agricultural irrigation systems. Moreparticularly, the invention relates to an improved track assembly for anirrigation system.

2. Background

Agricultural irrigation systems such as central pivot irrigationmachines and lateral move irrigation machines are commonly used toirrigate crops. A central pivot irrigation machine typically includes,among other things, a central pivot communicating with a pressurizedwater supply and a series of spans formed from mobile support towersconnected to the central pivot and to one another by truss-typeframework sections. A water distribution conduit is supported by theframework sections and a number of sprinkler heads, spray guns, dropnozzles, or other fluid-emitting devices are spaced along the length ofthe conduit. A lateral move irrigation system is similar except it doesnot include a central pivot but instead has several aligned spans thatmove laterally across a rectangular-shaped field.

The mobile towers of central pivot and lateral move irrigation systemsare typically supported on wheel and tire assemblies driven by suitablemotors. The wheel and tire assemblies sometimes slip, get stuck, and/orcreate ruts, especially in wet low-lying areas or on hills.

To alleviate these problems, a mobile tower's tires can be replaced withtrack assemblies similar to those installed on earth-movers andtractors. Track assemblies provide better traction and have a muchlarger footprint and better ground “floatation” and therefore don't getstuck, create ruts, or damage crops as much as tires do.

Unfortunately, known irrigation system track assemblies are complex andexpensive and therefore not practical for many applications. Moreover,known track assemblies sometimes provide too much traction and aretherefore difficult to guide in a circular or other non-straight pathwithout creating excessive stress on the irrigation system. In fact,applicant has discovered that known track assemblies can cause the spansof smaller irrigation systems to buckle while turning. Similarly,applicant has discovered that known track assemblies create excessoff-set loading on gearbox output shafts and other irrigation systemcomponents.

SUMMARY

The present invention provides an improved track assembly for irrigationsystems that doesn't suffer from the above-described problems and/orother problems. More particularly, the present invention provides atrack assembly with better traction and flotation than wheel and tireassemblies, but without the buckling and off-set loading problems ofexisting irrigation system track assemblies. The track assembly of thepresent invention is also less complex and costly than known irrigationsystem track assemblies and therefore more practical for manyapplications.

An embodiment of the track assembly is configured for replacing at leastone wheel on an irrigation system mobile tower and broadly comprises amounting bracket configured to be attached to the mobile tower; agearbox assembly and rotatable drive wheel hub attached to the mountingbracket; drive wheel attached to the drive hub; a rotatable tensionwheel hub attached to the mounting bracket and spaced from the drivehub; a tension wheel attached to the tension wheel hub; and a track belttrained over the drive wheel and the tension wheel and driven by thedrive wheel to propel the mobile tower.

In one embodiment, the mounting bracket is pivotally attached to one endof the mobile tower by a hinge plate and locking pin to permit the drivehub and attached drive wheel to turn slightly to more easily follow acurved path. The pivot angle of the mounting bracket relative to themobile tower may be adjusted with a simple eyelet or turnbuckle toachieve a preselected steering angle or tow.

The tension wheel hub may be shifted relative to the mounting bracket toadjust the distance between the drive wheel and the tension wheel andthus the tension of the track belt. In one embodiment, such adjustmentis achieved with a pair of spaced-apart walls on the mounting bracketthat define an adjustment channel. The tension wheel hub is mounted to asupport tube that can be moved along a length of the channel and fixedin place with bolts or other fasteners inserted through adjustment slotsin the mounting bracket.

In one embodiment, the drive wheel, tension wheel, and track belt areless than 13″ wide to minimize offset loading on the gearbox and topermit steering of the track assembly without excessive force on themobile tower. To keep the track belt centered on the drive wheel and thetension wheel, the drive wheel and the tension wheel each include anumber of spaced-apart outwardly projecting pegs that are receivedwithin spaced-apart holes on the track.

This summary is provided to introduce a selection of concepts in asimplified form that are further described in the detailed descriptionbelow. This summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Other aspectsand advantages of the present invention will be apparent from thefollowing detailed description of the embodiments and the accompanyingdrawing figures. For example, the principles of the present inventionare not limited to central pivot irrigation systems, but may beimplemented in other types of irrigation systems including linear moveirrigation systems.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Embodiments of the present invention are described in detail below withreference to the attached drawing figures, wherein:

FIG. 1 is a perspective view of an exemplary central pivot irrigationsystem on which the track assembly of the present invention may beimplemented.

FIG. 2 is a perspective view of one of the mobile towers of theirrigation system shown with two track assemblies installed thereon.

FIG. 3 is an enlarged perspective view in partial section of one of thetrack assemblies shown mounted to a drive tube of a mobile tower.

FIG. 4 is an exploded front perspective view of one of the mobile towersand its two track assemblies.

FIG. 5 is an exploded rear perspective view of one of the mobile towersand one of its track assemblies.

FIG. 6 is a top view in partial section of one of the mobile towers andits two track assemblies with the mobile tower shown in dashed lines andthe two track assemblies positioned to follow a straight path.

FIG. 7 is another top view in partial section of one of the mobiletowers and its two track assemblies with the mobile tower shown indashed lines and the two track assemblies positioned to follow acircular or other curved path.

The drawing figures do not limit the present invention to the specificembodiments disclosed and described herein. The drawings are notnecessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the invention.

DETAILED DESCRIPTION

The following detailed description of embodiments of the inventionreferences the accompanying drawings. The embodiments are intended todescribe aspects of the invention in sufficient detail to enable thoseskilled in the art to practice the invention. Other embodiments can beutilized and changes can be made without departing from the scope of theclaims. The following detailed description is, therefore, not to betaken in a limiting sense. The scope of the present invention is definedonly by the appended claims, along with the full scope of equivalents towhich such claims are entitled.

In this description, references to “one embodiment”, “an embodiment”, or“embodiments” mean that the feature or features being referred to areincluded in at least one embodiment of the technology. Separatereferences to “one embodiment”, “an embodiment”, or “embodiments” inthis description do not necessarily refer to the same embodiment and arealso not mutually exclusive unless so stated and/or except as will bereadily apparent to those skilled in the art from the description. Forexample, a feature, structure, act, etc. described in one embodiment mayalso be included in other embodiments, but is not necessarily included.Thus, the present technology can include a variety of combinationsand/or integrations of the embodiments described herein.

Turning now to the drawing figures, and initially FIG. 1, an exemplaryirrigation system 10 on which principles of the present invention may beimplemented is illustrated. The illustrated irrigation system 10 is acentral pivot irrigation system that broadly comprises a fixed centralpivot 12 and a main section 14 pivotally connected to the central pivot.The irrigation system 10 may also comprise an extension arm (alsocommonly referred to as a “swing arm” or “corner arm”) pivotallyconnected to the free end of the main section.

The fixed central pivot 12 may be a tower or any other support structureabout which the main section 14 may pivot. The central pivot has accessto a well, water tank, or other source of water and may also be coupledwith a tank or other source of agricultural products to injectfertilizers, pesticides and/or other chemicals into the water forapplication during irrigation.

The main section 14 may comprise a number of mobile support towers16A-D, the outermost 16D of which is referred to herein as an “endtower”. The support towers are connected to the fixed central pivot 12and to one another by truss sections 18A-D or other supports to form anumber of interconnected spans. The irrigation system 10 illustrated inFIG. 1 has four mobile support towers 16A-D; however, it may compriseany number of mobile support towers without departing from the scope ofthe present invention.

Each mobile tower may include a drive tube 20A-D on which a pair oftrack assemblies 22A-D is mounted. Embodiments of the track assemblies22A-D are described in more detail below. A drive motor 24A-D and driveshaft 26A-D are mounted to each drive tube 20 A-D for driving the trackassemblies. The motors 24A-D may include integral or external relays sothey may be turned on, off, and reversed. The motors may also haveseveral speeds or be equipped with variable speed drives. Instead oftrack assemblies, some of the mobile towers 16A-D may have wheels drivenby drive motors.

As is well known, the drive motors 24 A-D are controlled by a suitablesafety system such that they may be slowed or completely shut down inthe event of the detection of an adverse circumstance, all of which isdisclosed, for example, in U.S. Pat. No. 6,042,031 to Christensen, etal. incorporated herein by reference in its entirety.

Each of the truss sections 18A-D carries or otherwise supports a conduitsection 28A-D or other fluid distribution mechanism that is connected influid communication with all other conduit sections. A plurality ofsprinkler heads, spray guns, drop nozzles, or other fluid-emittingdevices are spaced along the conduit sections 28A-D to apply waterand/or other fluids to land underneath the irrigation system.

The irrigation system 10 may also include an optional extension arm (notshown) pivotally connected to the end tower 16D and supported by a swingtower with steerable wheels driven by a motor. The extension arm may bejoined to the end tower by an articulating pivot joint. The extensionarm is folded in relative to the end tower when it is not irrigating acorner of a field and may be pivoted outwardly away from the end towerwhile irrigating the corners of a field.

The irrigation system 10 may also include one or more high pressuresprayers or end guns 30 mounted to the end tower 16D or to the end ofthe extension arm. The end guns are activated at the corners of a fieldor other designated areas to increase the amount of land that can beirrigated.

The irrigation system 10 may also include a main control system forcontrolling movement of the mobile towers 16A-D and operation of thefluid-emitting devices in accordance with an irrigation design program.The main control system may include a processor or other computingdevice with inputs that receive positional information from one or moreGPS receivers mounted to the end tower or elsewhere. The processor mayalternatively receive position information from angle encoders mountedbetween the central pivot and a first span of the main section. Theprocessor may also include outputs connected to relay-controlled valvesconnected to the water-emitting devices and relay-controlled electricmotors connected to the drive wheels of the mobile towers.

Turning now to FIGS. 2-5, embodiments of the track assemblies 22A-D willnow be described in more detail. As shown, a mobile tower 16D mayinclude a pair of track assemblies, each of which broadly comprises amounting assembly 32; a gearbox assembly 34 and rotatable drive wheelhub 36; a drive wheel 38; a rotatable tension wheel hub 40; a tensionwheel 42; and a track belt 44. All of the track assemblies 22A-D areessentially identical; therefore only one track assembly 22D will bedescribed in detail below.

As best shown in FIGS. 4 and 5, the mounting assembly 32 is attached toone end of the drive tube 20D and is provided for supporting the othercomponents of the track assembly to the mobile tower 16D. An embodimentof the mounting assembly 32 includes a hinge plate 46 connected to thedrive tube 20D and a mounting bracket 48 pivotally connected to thehinge plate. The hinge plate 46 includes a vertically extending plate 50welded or otherwise fastened to one end of the drive tube 20D and a pairof spaced-apart, horizontally extending flanges 52 extending from thevertical plate. Vertically aligned pin holes 54 extend through theflanges 52 for receiving a locking pin 56 as described below. The hingeplate 46 also includes a rearwardly extending horizontal leg 58 that ispositioned below the drive tube 20D. A bolt hole or slot may bepositioned in the leg and aligned with a bolt hole on the mountingbracket as described below.

The mounting bracket 48 includes a vertically-extending plate 60 and apair of spaced-apart horizontally-extending flanges 62 extending fromthe vertical plate. Vertically aligned pin holes 64 extend through theflanges. The mounting bracket 48 may be attached to the hinge plate 46by placing the mounting bracket flanges 62 over the hinge plate flanges52 so as to align the holes 54 and 64, and then placing the locking pin56 through the holes 54 and 64. This arrangement permits the mountingbracket 48 to pivot relative to the hinge plate 46 and the drive tube20D so the track assembly 22D may turn slightly to follow a curved path.

A threaded eyelet or turnbuckle may attach the mounting bracket 48 tothe drive tube 20D or to the leg 58 of the hinge plate. The pivot angleof the mounting bracket may then be selected by adjusting the eyelet orturnbuckle to achieve a pre-selected steering angle or tow.Alternatively, a bolt may be positioned through a hole 66 in themounting bracket flange and into a slot in the hinge plate leg to adjustthe pivot angle of the bracket and the tow of the track assembly.

FIG. 6 shows one of the mobile towers 16D and its two truck assemblies22D in a straight line with no steering angle or tow. FIG. 7 shows thesame mobile tower and track assemblies with the track assemblies pivotedwith an approximate 3 degrees of tow.

The mounting bracket 48 further includes a pair of spaced-apart,horizontally extending guide walls 68 that define an adjustment channeltherebetween. A pair of slots 70 are formed in the vertical plate 60between the guide walls, the purpose of which are described below.

The gearbox assembly 34 and drive wheel hub 36 are conventional and areattached to the mounting bracket 48 by bolts, screws, or other fastenersthat extend through holes in the vertical plate of the bracket. Thegearbox assembly 34 is then coupled to the drive shaft 20D of the motor24D in a conventional manner.

The drive wheel 38 is attached to the drive wheel hub 36 by threaded lugnuts or other fasteners. In one embodiment, the drive wheel 38 isapproximately 40″ in diameter and 10″ wide. A drive wheel of this sizeallows the track assembly to more closely match the wheel speed of atire that has been replaced with the track assembly so that the gearbox34 is not required to provide a significant RPM reduction for the trackassembly as is required with prior art track assemblies.

The tension wheel hub 40 is rotatably mounted to a support tube 72 whichis in turn positioned within the adjustment channel of the mountingbracket. The support tube 72 and tension wheel hub 40 may be shiftedwithin the length of the adjustment channel to adjust the distancebetween the drive wheel 38 and the tension wheel 42 and fixed in placeby a pair of bolts or other fasteners that extend through bolt holes inthe support tube and the slots 70 between the guide walls in themounting bracket.

The tension wheel 42 is attached to the tension wheel hub 40 by lug nutsor other fasteners. The tension wheel 42 guides, tensions, and supportsthe track belt 44. Importantly, no undercarriage is required. In oneembodiment, the tension wheel 42 is approximately 24″ in diameter and10″ wide.

The track belt 44 is trained over the drive wheel 38 and the tensionwheel 42 and driven by the drive wheel. The track belt 44 may be made ofrubber or any other suitable material and may include any tread pattern.An embodiment of the track belt is 175″ long and 12″ wide. The narrowerwidth of the track belt, drive wheel, and tension wheel and the reducedlength of the track belt, when compared to existing track assemblies forirrigation systems, reduces the footprint of the track assembly so itcan be used with smaller irrigation systems without causing spanbuckling. Moreover, the reduced width creates less off-set loading onthe gearbox output shaft.

To keep the track belt 44 centered on the drive wheel and the tensionwheel, the drive wheel 38 and the tension wheel 42 each include a numberof spaced-apart outwardly projecting pegs 74 and the trac belt includesa number of spaced-apart holes 76 that receive the pegs.

Once the track assembly 22D is mounted to the mobile tower 16D asdescribed above, the tension in the track belt 44 can be adjusted byloosening the bolts holding the support tube 72 within the adjustmentchannel of the mounting bracket 48. The tension wheel hub 42 may then bemoved closer to the drive wheel hub 38 to reduce the tension on thetrack belt 44 or further from the drive wheel hub to increase thetension. In one embodiment, the tension wheel hub 42 and support tube 72may be moved by placing a conventional tire jack between the drive wheel38 and tension wheel 44 and adjusting it to achieve the desired tensionon the track belt.

As should be apparent from the above description, the present inventionprovides an improved track assembly for irrigation systems that doesn'tsuffer from the problems of prior art irrigation system trackassemblies. For example, the track assembly has better traction andflotation than wheel and tire assemblies but does not create thebuckling and off-set loading problems of prior art irrigation systemtrack assemblies. The track assembly of the present invention is alsoless complex and costly than known irrigation system track assembliesand is therefore practical for use with nearly any irrigation system.

Although the invention has been described with reference to theembodiments illustrated in the attached drawing figures, it is notedthat equivalents may be employed and substitutions made herein withoutdeparting from the scope of the invention as recited in the claims. Forexample, the principles of the present invention are not limited to theillustrated central pivot irrigation systems but may be implemented inany type of irrigation system including linear move irrigation systems.

Having thus described the preferred embodiment of the invention, what isclaimed as new and desired to be protected by Letters Patent includesthe following:

Having thus described the preferred embodiment of the invention, what isclaimed as new and desired to be protected by Letters Patent includesthe following:
 1. A track assembly for a mobile tower of an irrigationsystem, the track assembly comprising: a mounting bracket configured tobe attached to the mobile tower; a gearbox assembly and rotatable drivewheel hub attached to the mounting bracket; a drive wheel attached tothe drive wheel hub; a rotatable tension wheel hub attached to themounting bracket and spaced from the drive wheel hub; a tension wheelattached to the tension wheel hub; and a track belt trained over thedrive wheel and the tension wheel and driven by the drive wheel topropel the mobile tower, wherein the mounting bracket includes a pair ofspaced-apart guide walls that define an adjustment channel, wherein thetension wheel hub is mounted to a support tube that can be moved along alength of the channel to adjust the tension of the track belt.
 2. Thetrack assembly as set forth in claim 1, wherein the mobile towerincludes a drive tube, wherein the track assembly further includes ahinge plate for mounting to the drive tube and wherein the mountingbracket is configured to be pivotally attached to one end of the drivetube.
 3. The track assembly as set forth in claim 1, wherein the drivewheel and the tension wheel each include a number of spaced-apartoutwardly projecting pegs and the track belt includes a number ofspaced-apart holes that receive the pegs to keep the track centered onthe drive wheel and the tension wheel.
 4. The track assembly as setforth in claim 1, wherein the drive wheel, the tension wheel, and thetrack belt are all less than 13″ wide.
 5. The track assembly as setforth in claim 1, wherein the track belt is tensioned by the tensionwheel alone without an undercarriage.
 6. A track assembly for a mobiletower of an irrigation system, the mobile tower having a drive tube, thetrack assembly comprising: a hinge plate for attachment to one end ofthe drive tube; a mounting bracket pivotally attached to the hingeplate; a gearbox assembly and rotatable drive wheel hub attached to themounting bracket; a drive wheel attached to the drive wheel hub; arotatable tension hub attached to the mounting bracket and spaced fromthe drive wheel hub, the tension wheel hub being shiftable relative tothe mounting bracket and the drive wheel hub; a tension wheel attachedto the tension wheel hub; a track belt trained over the drive wheel andthe tension wheel and driven by the drive wheel to propel the mobiletower, wherein the mounting bracket includes a pair of spaced-apartguide walls that define an adjustment channel, wherein the tension wheelhub is mounted to a support tube that can be moved along a length of thechannel to tension the track belt.
 7. The track assembly as set forth inclaim 6, wherein the hinge plate includes a pair of spaced-apart flangeswith vertically aligned holes, wherein the mounting bracket includes apair of spaced-apart flanges with vertically-aligned holes, and whereinthe mounting bracket is pivotally attached to the hinge plate with alocking pin that fits through the aligned holes.
 8. The track assemblyas set forth in claim 6, wherein the drive wheel and the tension wheeleach include a number of spaced-apart outwardly projecting pegs and thetrack includes a number of spaced-apart holes that are engaged by thepegs to keep the track centered on the drive wheel and the tensionwheel.
 9. An irrigation system comprising: a central pivot; a series ofmobile towers connected to the central pivot and to one another bysupport structure, each mobile tower having a drive tube, a drive motor,and a drive shaft driven by the drive motor; and at least one trackassembly for supporting at least one of the mobile towers above a groundto be irrigated by the irrigation system, the track assembly comprising:a mounting bracket configured to be attached to the mobile tower; agearbox assembly and rotatable drive wheel hub attached to the mountingbracket; a drive wheel attached to the drive wheel hub; a rotatabletension wheel hub attached to the mounting bracket and spaced from thedrive wheel hub; a tension wheel attached to the tension wheel hub; atrack trained over the drive wheel and the tension wheel and driven bythe drive wheel to propel the mobile tower, wherein the mounting bracketincludes a pair of spaced-apart guide walls that define an adjustmentchannel, wherein the tension wheel hub is mounted to a support tube thatcan be moved along a length of the channel to tension the track belt.10. The irrigation system as set forth in claim 9, further comprising: awater distribution conduit supported by the support structure; and anumber of fluid-emitting devices connected to the water distributionconduit.
 11. The irrigation system as set forth in claim 9, wherein thedrive wheel, the tension wheel, and the track belt are all less than 13″wide.
 12. The irrigation system as set forth in claim 9, wherein thetrack belt is tensioned by the tension wheel alone without anundercarriage.